The present invention relates in general to the art of fuel regulators, and more in particular, to such regulators as used with internal combustion engines.
Many of today's internal combustion engines are supercharged. In fuel injected, supercharged engines, fuel drawn by a fuel pump from a fuel tank goes to a fuel rail. The fuel rail supplies the injectors of an engine. Fuel demand is a function of engine speed and load, and resulting vacuum.
A regulator determines the amount of fuel the injectors receive, and that amount is a function of demand. The regulator has a spring loaded diaphragm, and a bypass valve. The diaphragm separates the interior of the regulator into fuel and spring chambers. The bypass valve passes fuel out of the fuel chamber through a fuel passage, say a nipple. Fuel enters the chamber through a different passage, say different nipples. The spring chamber houses the spring and sees manifold pressure. The spring tends to close the bypass valve, and prevent fuel from leaving the chamber. The fuel chamber sees fuel pressure, which opposes the spring force and tends to open the bypass valve. As vacuum increases the net bypass valve closing force on the diaphragm decreases, and when fuel pressure in the rails exceeds a preset value, the force of the fuel pressure unseats the bypass valve, and fuel returns to the fuel tank. Thus, fuel pressure to the engine is regulated.
The result of this regulation is a compensation of in a 1:1 relationship. Thus, an increase in supercharger boost pressure of 5 psi. results in an increase of fuel pressure of 5 psi.
It is highly desirable to increase fuel pressure as boost pressure increases at a rate sufficient to compensate for an increased air flow rate of a supercharged engine.
It is also highly desirable to return to standard fuel pressure settings and regulation when augmented fuel pressure is not needed.